What is the ostrich nest made of?

Ostrich nests are not "made" out of anything. They are instead constructed by a male by the digging out a shallow pit in the dirt where the community's female ostriches then lay the eggs. The dominant female of the group may discard some of the other ostriches's eggs when it is her time to lay. They are used as a community base for the eggs with the females incubating them by day and the males incubating them by night.